Grab the ZKK - which ever one!
Never heard of a ZKK600 in 9.3x64, in the smaller 62 yes & if I'm correct it was also made in the 10.75x68mm?
It must have been just a "European" offering only, not the market or numbers here in Oz!
I had one in 7x64 - still regret selling it, problem is it (partly) financed getting my .404!
Bugger had the peep sight too!
Difficult choice to make Karl.
Like grandveneur I started with a Mauser - primarily because that is what Mr Wilhelm Brenneke used, more options if you go via the Mauser route though. Buy the bottom metal later, sights, scope etc in stages.
Best of luck with the project - glad to see someone's recognising a great calibre!
93x64mm